Augmented reality for data curation

ABSTRACT

Particular embodiments may receive signals periodically detected by a mobile device and transmitted by multiple fixed-location signal sources within an environment, wherein the mobile computing device includes at least a camera. A spatial distribution of signal strengths is determined based on the detected signals, and relative positions of the mobile computing device are identified using the detected spatial distribution of signal strengths. The system may receive and analyze the images of the environment captured by the camera and calibrate the relative positions using the image analysis results. A map of spatial distribution of signal strengths is created by correlating the spatial distribution of signal strengths with the calibrated relative positions.

TECHNICAL FIELD

This disclosure generally relates to location tracking, and in particular to systems and methods for location tracking using augmented reality.

BACKGROUND

Augmented Reality (AR) effects are computer-generated visual effects (e.g., images and animation) that are superimposed or integrated into a user's view of a real-world scene. Certain AR effects may be configured to track objects in the real world. For example, a computer-generated unicorn may be placed on a real-world table as captured in a video. The augmented effect may be presented in a variety of ways. For example, the real-world table may be captured by the camera of a mobile smartphone and displayed in real-time through the device's display. In addition to displaying the table, the computing device may also display the unicorn, integrating it with the video of the table that is being displayed. As another example, a user may be viewing the real-world through AR glasses or viewing optics. Like regular glasses, the AR glasses may have one or more lenses that are translucent so that the user may see real-world objects through the lenses. A computer-generated unicorn may be projected onto the lenses so that the unicorn is seen along with any real-world object that is visible through the lenses.

A mobile computing device, such as a smartphone, tablet computer, or laptop computer, may include functionality for determining its location, direction, or orientation, such as a GPS receiver, compass, gyroscope, or accelerometer. Such a device may also include functionality for wireless communication, such as BLUETOOTH communication, near-field communication (NFC), or infrared (IR) communication or communication with a wireless local area networks (WLANs) or cellular-telephone network. Such a device may also include one or more cameras, scanners, touchscreens, microphones, or speakers. Mobile computing devices may also execute software applications, such as games, web browsers, or social-networking applications. With social-networking applications, users may connect, communicate, and share information with other users in their social networks.

SUMMARY OF PARTICULAR EMBODIMENTS

Embodiments described herein relate to systems and methods of tracking locations using AR. Conventional systems may comprise a plurality of fixed-location signal sources transmitting signals in a particular environment, and a mobile device can detect these signals transmitted from the fixed locations periodically. Depending on the distance from the mobile device to the signal sources, the strengths of the detected signals are different, and a spatial distribution of signal strengths can be formed by the systems. By knowing the locations of the fixed-location signal sources relative to the environment, given the detected distribution of signal strengths, the systems can identify the mobile device's locations relative to the environment. However, the mobile device's locations identified mainly by the spatial distribution of signal strengths may not reach a desired accuracy level due to various factor, such as interference of other signal sources or obstruction of obstacles of the environment.

Meanwhile, in various embodiments described herein, a camera of the mobile device can capture a plurality of images of the environment. By analyzing the captured images using the AR techniques, the systems described herein may be able to obtain more accurate space information of the environment or orientation information of the mobile device, and the obtained information can be used to calibrate the identified mobile device's locations to improve accuracy of the locations. The detected spatial distribution of signal strengths can be correlated with the identified mobile device's locations, and a map of the spatial distribution of signal strengths may be created and saved on a server in the systems and may be accessed by other users of the systems. Given a specific distribution of signal strengths detected by a mobile device, the systems can precisely identify the mobile device's location on the map of the spatial distribution of signal strengths. The systems may further refine or update the map with subsequently detected signal data. AR contents at the respective exact locations can be shown on the map and provided to the user for display.

In a particular embodiment, motion sensors of the mobile device can detect motion signals of the mobile device. The motion sensors may include an accelerometer, a compass, an altimeter, a gyroscope, or any other sensors that can sense the mobile device's movement. For example, the gyroscope can determine the orientation of the mobile device and measure the change of orientation (e.g., rate of rotation.) The accelerometer can measure non-gravitational acceleration of the mobile device. By combining the motion information detected or measured by the motion sensors and the images captured by the camera, the system may be able to determine the mobile device's orientation and movement precisely and further calibrate the mobile device's location more accurately. The detected spatial distribution of signal strengths can be correlated with the identified mobile device's locations, and a map of the spatial distribution of signal strengths may be created and saved on a server in the systems and may be accessed by other users of the systems. Given a specific distribution of signal strengths detected by a mobile device, the systems can precisely identify the mobile device's location on the map of the spatial distribution of signal strengths. The systems may further refine or update the map with subsequently detected signal data. AR contents at the respective exact locations can be shown on the map and provided to the user for display.

Embodiments may include or be implemented in conjunction with an artificial reality system. Artificial reality is a form of reality that has been adjusted in some manner before presentation to a user, which may include, e.g., a virtual reality (VR), an augmented reality (AR), a mixed reality (MR), a hybrid reality, or some combination and/or derivatives thereof. Artificial reality content may include completely generated content or generated content combined with captured content (e.g., real-world photographs). The artificial reality content may include video, audio, haptic feedback, or some combination thereof, and any of which may be presented in a single channel or in multiple channels (such as stereo video that produces a three-dimensional effect to the viewer). Additionally, in some embodiments, artificial reality may be associated with applications, products, accessories, services, or some combination thereof, that are, e.g., used to create content in an artificial reality and/or used in (e.g., perform activities in) an artificial reality. The artificial reality system that provides the artificial reality content may be implemented on various platforms, including a head-mounted display (HMD) connected to a host computer system, a standalone HMD, a mobile device or computing system, or any other hardware platform capable of providing artificial reality content to one or more viewers.

The embodiments disclosed herein are only examples, and the scope of this disclosure is not limited to them. Particular embodiments may include all, some, or none of the components, elements, features, functions, operations, or steps of the embodiments disclosed above. Embodiments according to the invention are in particular disclosed in the attached claims directed to a method, a storage medium, a system and a computer program product, wherein any feature mentioned in one claim category, e.g. method, can be claimed in another claim category, e.g. system, as well. The dependencies or references back in the attached claims are chosen for formal reasons only. However, any subject matter resulting from a deliberate reference back to any previous claims (in particular multiple dependencies) can be claimed as well so that any combination of claims and the features thereof are disclosed and can be claimed regardless of the dependencies chosen in the attached claims. The subject-matter which can be claimed comprises not only the combinations of features as set out in the attached claims but also any other combination of features in the claims, wherein each feature mentioned in the claims can be combined with any other feature or combination of other features in the claims. Furthermore, any of the embodiments and features described or depicted herein can be claimed in a separate claim and/or in any combination with any embodiment or feature described or depicted herein or with any of the features of the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example floor map in an environment for tracking locations in particular embodiments.

FIG. 2 illustrates an example method of tracking locations using AR in particular embodiments.

FIG. 3 illustrates an example network environment associated with a social-networking system in particular embodiments.

FIG. 4 illustrates an example social graph in particular embodiments.

FIG. 5 illustrates an example computer system in particular embodiments.

DESCRIPTION OF EXAMPLE EMBODIMENTS

There are some systems configured to determine and track positions of users by mobile devices. A global positioning satellite (GPS) system is one of the many systems of tracking outdoor locations. However, in certain situations, the GPS system is unavailable or cannot be used in a certain environment (e.g., indoors or underground). In these cases, determining and tracking positions within a defined local area can be performed using a local area network, wherein the local area network can comprise a plurality of fix-location signal sources (e.g., access points (APs).) The APs are bi-directional communication ports for the mobile devices to communicate with the local area network, wherein the APs can be configured to receive signals from the mobile devices or transmit signals to the mobile devices in the local area network.

In such systems, the mobile devices' absolute location, such as an address of a building, can be first identified using the GPS or other global location signals. Then the mobile devices' relative locations with respect to the environment (e.g., inside the building) can be identified using the indoor location tracking systems, which are configured to determine and track locations using the local area network when the GPS signals are not available, or the GPS system cannot be used.

Conventionally, a user (e.g., a human user or a robot) can move around the particular environment with a mobile device. While the user walks around, the mobile device can periodically detect wireless signals transmitted from the APs and collect distributions of detected wireless signal strengths at a plurality of sampling locations (e.g., where the user arrives every five seconds). Depending on the distance from the mobile device to the APs, the strengths of the wireless signals can be detected differently, such that the signal transmitted from the closet AP can have the strongest detected signal strengths and the signal transmitted from an AP far away from the user may be too weak to be detected. At each sampling location, the mobile device can detect a set of signals transmitted from the nearby APs, and a corresponding distribution of signal strengths can be collected. By knowing the locations of the APs and the distribution of signal strengths, the system can identify the location of the mobile device.

Although the locations of the APs may be carefully selected to avoid interference from other signal sources or obstructions affecting the transmission or reception capabilities of the access points (e.g., walls), the transmission or reception of the signals may still be affected due to various reasons. Thus, the conventional method may not be able to identify the locations of the mobile device to be associated with the collected signal strength profiles to a desired level of precision due to various reasons. Additionally, using WI-FI or BLUETOOTH may not be able to precisely identify the mobile device's locations to the desired degree as well.

In particular embodiments described herein, as the user walks around the environment (e.g., shopping mall), the user's smartphone can periodically scan the signals every five seconds at a sampling location, for example, to create a list of scatter points, wherein the list of scattered points can be normalized to form a grid. The distribution of wireless signal strengths associated with each scattered point in the grid can be interpolated to form a spatial distribution of wireless signal strengths. The spatial distribution of wireless signal strengths can be correlated with the user's relative locations with respect to the starting point, wherein the user's relative locations can be calibrated (e.g., using AR techniques) for improving the accuracy, and a map of spatial distribution of signal strengths with respect to the correlation results can be created and saved in the server of the systems, wherein the correlation results can be implemented or represented in various manners including arrays or matrixes. Upon receiving a location ping request from a server in the systems, the smartphone can identify its location by analyzing the signal scans.

In particular embodiments, systems and methods can track user's locations by user's mobile device (e.g., a smartphone) using AR. The systems and the methods may use image data captured by a camera (e.g., a smartphone's build-in camera) to obtain locations and the space information of the user's surroundings or orientation of the user's mobile device by analyzing the images. The captured images/videos can be processed by an AR application using AR techniques, wherein the AR application may accurately identify the user relative locations with respect to a starting point. By analyzing the captured images, the angles of capturing the images, or the sequence of capturing the images, the system can determine user's orientation and movement, such as moving forward/backward, or turning right/left, etc. Locations and space information can be obtained by analyzing the user's orientation and movement, and the system can calibrate the locations identified by the distribution of detected signal strengths with the image analysis results. Thus, the locations identified using the AR techniques can be more accurate. Further, the identified locations correlated with the spatial distribution of signal strengths detected by the smartphone can be saved, and a map of the identified locations with respect to the spatial distribution of signal strengths can be generated and saved on a server of the system.

Once the map of spatial distribution of signal strengths is created, the map can be further refined and updated with subsequently collected spatial distribution of signal strengths from multiple users' mobile devices. The map of spatial distribution of signal strengths may be created by a prior user in particular embodiments and can be accessed by a subsequent user of the system. The subsequent user's mobile device can detect spatial distribution of signal strengths by scanning the APs in the same environment periodically. Based on the spatial distribution of signal strengths detected by the subsequent user's mobile device, the system can precisely identify the corresponding subsequent user's locations on the map of spatial distribution of signal strengths. The systems described herein can track a user's locations more accurately by using AR techniques.

As described above, the system may comprise two phases, a first phase of creating an accurate map of spatial distribution of signal strengths and a second phase of using the map of spatial distribution of signal strengths for identifying mobile device's locations. During the first phase, identifying locations using the AR techniques and detecting the spatial distribution of signal strengths at sampling locations can be operated concurrently. The map of spatial distribution of signal strengths can be created by correlating the detected spatial distribution of signal strengths and the identified user locations. During the second phase, the map of spatial distribution of signal strengths can be used for identifying a subsequent user's location based on the spatial distribution of signal strengths detected by the subsequent user's mobile device. Meanwhile, the map of spatial distribution of signal strengths can be further refined or updated by crowdsourcing the collection of the signal strengths. The spatial distribution of signal strengths newly detected by the subsequent users' mobile devices around the same shopping mall over a certain period of time can be used to fill gaps of the map or to refine the map by interpolating with existing distributions of signal strengths.

In particular embodiments, systems and methods can track user's exact locations by user's mobile device (e.g., a smartphone) using augmented reality (AR). The systems and the methods may use image data (e.g., captured images or videos) and motion data (e.g., movement or orientations) detected by motion sensors of the smartphone to obtain the space information of the user's surroundings and more accurately detect user's orientation or movement. The image data can be analyzed as described above. Additionally, the system can determine user's movement and orientation more accurately by analyzing the motion data, such as the mobile device's orientation, speed, or altitude. Combined with the image data, the system can determine user's orientation or movement more precisely, wherein the user's orientation may be detected by a gyroscope or the acceleration may be detected by an accelerometer. The space information obtained by analyzing the images and the motion data can be more accurate than by analyzing the images only. The user's locations can be identified more precisely with the support of the image data and the motion data. The identified user's location then can be correlated with the detected spatial distribution of signal strengths, and a map of the spatial distribution of signal strengths with respect to the detected spatial distribution of signal strengths can be generated and saved on a server of the system. Thus, the accuracy of the identified mobile device's location can be further improved by analyzing the motion data and analyzing the images using AR techniques.

As described previously, the map of spatial distribution of signal strengths can be further refined or updated with subsequently collected spatial distribution of signal strengths from multiple users' mobile devices. The refined or updated map of spatial distribution of signal strengths may be accessed by a subsequent user of the system, and the subsequent user's locations can be identified with respect to the distribution of signal strengths detected by the subsequent user. The AR tracking techniques described herein can track a user's locations more accurately by analyzing image data and the motion data.

In some embodiments, systems and methods using AR tracking techniques can be more robust and accurate for tracking mobile device's locations by correlating the identified locations with the spatial distribution of signal strengths, and a map of spatial distribution of signal strengths with respect to the identified locations can be created by the correlation results in the first phase. In the second phase, the systems may precisely identify a user's locations based on the map of spatial distribution of signal strengths with respect to a detected distribution of signal strengths. The systems and the methods described herein, can identify the user's locations faster and more precisely.

In particular embodiments, tracking objects of interest in the real-world scene may use one or more AR tracking algorithms, wherein the AR tracking algorithms may include, but not limited to, Simultaneous Localization and Mapping (SLAM) algorithm, environment-tracking algorithm, face-tracking algorithm, or hand-tracking algorithm. In particular embodiments, different objects or regions within the same scene may be tracked using different AR tracking algorithms. For example, a user's face may be tracked using a face-tracking algorithm, tables and bookcases may be tracked using SLAM, and a pet may be tracked using region tracking.

In particular embodiments, the AR application may be configured to select AR tracking algorithms based on objects' characteristics and computational costs. For example, an AR application may use AR tracking algorithms with high computational costs (e.g., SLAM and face-tracking algorithms), AR tracking algorithms with medium computational costs (e.g., region-tracking algorithms), and AR tracking algorithms with low computational costs (e.g., based on gyroscope data without image processing). In particular embodiments, the AR application may switch among the algorithms based on their respective characteristics and device configurations. For example, the AR application may select the most accurate tracking algorithm (e.g., SLAM or face-tracking algorithm) as long as the system can handle the cost of expensive computation. When the system determines that the computational cost is too high, the AR application may switch to a relatively less accurate tracking algorithm (e.g., region-tracking algorithm) that is relatively less computationally expensive. In particular embodiments, the AR application may dynamically switch from one tracking algorithm to another during an AR session without the user ever being aware that the switching occurred. By selecting an appropriate AR tracking algorithm, the AR application is able to provide the optimum results with respect to the system configurations. In particular embodiments, when the AR application transitions from one tracking algorithm (e.g., SLAM) to another (e.g., region-tracking algorithm), the depth information is modeled and understood by SLAM but not be understood by the region-tracking algorithm. Thus, when transitioning from one tracking algorithm to another tracking algorithm, the AR application may transform the tracking data (e.g., depth information) into tracking data compatible with or understood by another algorithm.

In particular embodiments, the AR application may be built on AR software development platforms, such as ARKIT or ARCORE, to enable scene tracking and display virtual objects in the user's view. The AR software development platform can enable the AR application to track the user's real-world surroundings and sense the user AR device or mobile device's orientation and position relative to the environment in the user's view by taking advantage of user mobile device's built-in hardware of cameras and sensors, including motion sensors and camera sensors. The AR application can place 2D or 3D virtual objects in the user's real-world scene, wherein the orientation, dimensions, or position of the virtual objects can be adjusted based on the user's real-world scene, such as space information discussed previously.

FIG. 1 illustrates an example floor map of an environment for tracking locations in particular embodiments. FIG. 1 shows the floor map of a section of an environment 100, such as a shopping mall. The floor map may comprise a plurality of access points (APs) including APs 110 a, 110 b, 110 c, and 110 d, wherein the APs can transmit wireless signals continuously. A user holding a mobile device (e.g., a smartphone) may activate a location tracking system at a starting point 120. As the user walks around the shopping mall, the smartphone can sample the signals transmitted from the APs periodically at a plurality of sampling locations including sampling locations 130 a, 130 b, 130 c, 130 d, 130 e, 130 f, 130 g, 130 h, and 130 i. At each sampling location, signal strengths can be detected, and distribution of signal strengths can be collected. A spatial distribution of signal strengths can be formed with respect to the collected distribution of signal strengths.

The user's absolute location, such as the street address or coordinates of longitude and latitude of the shopping mall, maybe identified by GPS signals. The user's absolute location can also be identified by the user's social networking activities, such as the location information from the timeline of a user's account.

In particular embodiments, the user's smartphone may scan signals periodically (e.g., every ten seconds) from the APs 110 a, 110 b, 110 c, and 110 d, and collect distributions of signal strengths at each sampling location marked in FIG. 1. For example, at the sampling location 130 b, the signal strength detected from the AP 110 c is the strongest, the signal strengths detected from the AP 110 a and AP 110 d are weaker, and the signal strength detected from the AP 110 b is the weakest. The distribution of signal strengths at the sampling location 130 b can be collected.

In ten seconds, the user may walk to the next sampling location (e.g., sampling location 130 c). The mobile device scans signal strengths form the APs, and the distribution of signal strengths can be collected at the respective sampling location 130 c again. Similarly, in another eighty seconds, at the sampling location 130 e, the signal strengths detected from the AP 110 c and AP 110 d may be stronger, while the signal strengths detected from the AP 110 a and AP 110 b are weaker. The distribution of signal strengths at the sampling location 130 e can be collected.

In the above example, the mobile device may repeatedly scan the signals transmitted from the APs every ten seconds or any other suitable time interval, the distribution of detected signal strengths may be collected at a corresponding sampling location. The spatial distribution of signal strengths can be formed by interpolating the distribution of signal strengths collected at each sampling location. Knowing the locations of the APs, the mobile device's location can be identified. However, as discussed previously, the location of the mobile device may not be identified accurately to a desired level.

As discussed previously, the system can identify the user's relative locations with respect to the environment 100 using AR tracking techniques. In particular embodiments, the user's mobile device (e.g., a smartphone) may be used for capturing the images or videos of the environment 100, such as interior images of the shopping mall. Alternatively, an AR device may be used for capturing images, such that the user may walk around the shopping mall wearing a head mounted AR device having built-in cameras.

The images can be processed by an AR application using respective AR algorithms, wherein the AR algorithms may be determined based on various factors as described previously. For example, a user starts walking from the starting point 120. The system can track his locations and trace his path comprising a plurality of sampling locations including 130 a, 130 b, 130 c, 130 d, 130 e, 130 f, and 130 g. The built-in camera on the user's smartphone captures images of the environment 100 including a plurality of stores 150, 160, 170 and 172. The images captured at the sampling location 130 b may comprise user's surroundings including the stores 170, 150, and 172. In this example, by analyzing the captured images and angles of capturing the images, the system may determine that the store 150 is closer to the user than the stores 170 and 172. By analyzing a set of images captured at the sampling location 130 b, the system may determine the user's orientation such that the user turns to his left, and the stores 150 and 172 are at user's left and the store 170 is at user's right. Further, by analyzing the orientations and dimensions of objects in the set of images captured at the sampling location 130 b, the system may determine that the distance from the user to the store 150 is five feet and distance to a wall 174 is ten feet. Thus, the system can obtain some of the space information such that the width of the hallway is approximately fifteen feet.

If a second set of images are captured at the sampling location 130 b when the user turns to his right, by analyzing the orientations and dimensions of the objects in the second set of images, the system may more accurately determine that the distance from the user to the wall 174 is eleven feet, for example. When the user looks up, the system may analyze the captured images and determine the height of the ceiling. Thus, in some embodiments, accuracy of the space information can be improved when there are more image data available for analysis. Similarly, the system may identify the locations of some obstacles in the shopping mall (e.g., walls or table/chair set 176), and map those obstacles of the environment 100 to a 3D floor map. Thus, the system may be able to accurately layout the shopping mall interior and mark the obstructions.

In particular embodiments, by tracking the changes of perception of the objects, the system may further identify objects in the images, detect the position, topology, and depth (e.g., distance) of the objects, find horizontal or vertical planes in the scenes, and place or track the virtual objects in the scene accordingly. For example, the system may recognize humans in the captured images. By tracking the movement of the humans, the system may be able to identify the entrance to the store 150 when customers enter or exit the store 150. Further, by analyzing the objects (e.g., logos or display windows) in the images, the system may determine that the store 150 is a bookstore and the dimensions of the bookstore, and the store 150 can be accurately mapped on the map. In particular embodiments, the AR application may use computer vision technologies (e.g., SLAM or other depth-sensing technologies and object-recognition technologies) to determine where the ground is relative to the user and position of the objects on the ground on the AR display at the appropriate distance from the user.

In particular embodiments, the system can identify the user's locations more precisely using the AR techniques. The identified locations can be correlated with the spatial distribution of signal strengths and a map of spatial distribution of signal strengths can be created. The map of spatial distribution of signal strengths can be refined or updated by the subsequently detected distribution of signal strengths and saved on a server of the system. The map of spatial distribution of signal strengths can be used by the system to identify other user's locations, when a specific distribution of signal strengths is provided. Thus, the accuracy of the map of spatial distribution of signal strengths can be improved, and the location tracking using AR techniques can be more accurate as well.

In particular embodiments, the system may create a virtual path leading the user to a certain destination, wherein the virtual path may comprise virtual lines and arrows pointing to the precise direction superimposed in the real-world scene, and the virtual path can be provided to the user for display on user's phone screen or AR head mounted device. With the accurate map of spatial distribution of signal strengths, the virtual path may be created precisely, and the obstacles can be avoided. For example, by knowing the table/chair set 176 is fourteen feet from the user's current location, the virtual path may guide the user to turn diagonally to avoid the obstruction. When creating a virtual path leading the user to the store 150, the system may create the virtual path precisely leading the user to the entrance of the store 150 and avoiding the walls or glass window displays.

When the system identifies that the user's location is close to the store 150 and the user's moving direction is toward the store 150, the AR contents (e.g., coupons of the bookstore) can be shown at the exact location of the store 150 in the user's view (e.g., smartphone screen).

In particular embodiments, the mobile device may obtain the sensor signals detected by the various sensors of the mobile device. In addition to the image data, the system may also analyze the detected sensor signals and accurately track the user's movement and orientation. The various sensors can comprise camera sensors or motion sensors including an accelerometer, a compass, an altimeter, a gyroscope, or any other sensors that can sense the mobile device's movement. In some examples, the sensor of the mobile device can include a gyroscope and/or an accelerometer that can accurately indicate the mobile device's orientation and acceleration, respectively. For example, the gyroscope can determine the orientation of the mobile device and measure the change of orientation (e.g., rate of rotation.) The accelerometer can measure non-gravitational acceleration of the mobile device. By combining the information detected or measured by the gyroscope and accelerometer, the system may be able to determine the mobile device's orientation and movement precisely and further identify the mobile device's location more accurately.

For example, at the sampling location 130 h, the accelerometer may detect that the acceleration is zero and the gyroscope may measure the rate of rotation is eighty degrees to the left. The system can determine that the user stops and turns left eighty degrees at the sampling location 130 h by analyzing the detected motion data. The system may also determine the distance between the sampling location 130 h and sampling location 130 e, by knowing the travel time (e.g., fifty seconds), acceleration, and the degree of rotation (e.g., straight line with zero-degree rotation). By analyzing the combined the motion data and image data using the AR tracking techniques, the system may determine the location and dimensions of the store 150 more accurately. The motion sensors may detect that the user's moving direction (e.g., forward or backward), and the system may determine that the user approaches/leaves the store 160 accordingly. When the user walks around the entire environment 100, the system can map the entire environment 100 into the 3D floor map, and the precise space information can be integrated in the map.

By utilizing the detected spatial distribution of signal strengths and analyzing image data and the motion data using AR techniques, the system can create a very detailed and precise map of spatial distribution of signal strengths and identify the relative locations of the user in the environment 100 more accurately. The map can be refined or updated with subsequently detected signal strengths.

For example, as shown in FIG. 1, the first user walks along the path 180 shown in dashed line but does not visit the store 170. The map of spatial distribution of signal strengths created with respect to the first user's locations may have gaps around the location of the store 170. The location information around the store 170 may not be identified to a desired level of precision. Subsequently, a second user may walk down the store 170 along the route 182. The images captured by the second user can have more details than the images captured by the first user, and the store 170 can be mapped more accurately based on analyzing the image data captured by the second user's. The second mobile device may scan signal strengths at the locations shown in FIG. 1 including the sampling locations 130 b and 130 i, and the map of spatial distribution of signal strengths can be updated with the data collected by the second user. At the sampling location 130 i, the signal strength collected from the AP 110 d is the strongest, the signal strength collected from the AP 110 c is weaker, and signal strengths collected from the AP 110 a and AP 110 b are the weakest. Therefore, the map of spatial distribution of signal strengths may be updated by filling the gaps around the store 170 with the distributions of signal strengths detected by the second user. The updated map of spatial distribution of signal strengths can be saved in the system and can be used to identify locations or further be updated by subsequent detected data.

In particular embodiments, the map of spatial distribution of signal strengths can be stored in the system and can be accessed by other users of the system. For example, when a third user walks in the shopping mall, the third user's mobile device can scan signals periodically, and corresponding distributions of signal strengths can be collected at different locations. Based on the distributions of signal strengths detected by the third user, the third user's locations can be precisely identified on the map of spatial distribution of signal strengths. In accordance with the identified precise location, the system may promote coupons or advertisement of the stores near the third user location for display or send the third user a virtual path guiding the third user to a particular location. For example, at the sampling location 130 b, the promotion coupons or advertisement of the store 150 may appear at the exact location of the store 150. As the third user walks toward the store 170, the coupons of the store 150 may disappear, instead, the promotions of the store 170 may appear at the exact location of the store 170. In this example, the system can update the map of spatial distributions of signal strengths by the distributions of signal strengths detected by the third user.

In particular embodiments, the altimeter of the mobile device may detect the altitude changes. For example, the system can determine that the user is going up to the second floor based on the altitude detected by the altimeter. By knowing that the user is at the second floor, the system may be able to map the environment of the second floor accordingly. Similarly, at each floor of the shopping mall, the environment can be mapped accurately, and a corresponding map of spatial distribution of signal strengths can be created accordingly. Thus, the system described herein can map the particular environment more precisely and the accuracy of location identification can be significantly improved.

As described previously, the AR contents may be shown at respective exact locations in the user's view. In particular embodiments, the AR contents may be prioritized before they are sent to the user. For example, by analyzing the captured images or the motion data, the system may be able to determine that the user just purchased a cookie at a bakery. The system may prioritize a nearby coffee shop and promote the coffee shop to the user. A virtual path can be created for guiding the user to the coffee shop and the coupons can be shown at exact locations of the coffee shop in the user's view.

In particular embodiments, the AR contents may be sent to the user for display in user's view, such as on user's mobile device's screen. Alternatively, the AR content may be provided to the user by other manners, such as voice commands or text messages. For example, instead of displaying a virtual path on the user's mobile device's screen, the system may send the user voice commands, such as “turn right”, “go upstairs”, or “stop”, etc.

In particular embodiments, when an access point is not encountered by users for a predetermined amount of time, such as, for example, if the AP 110 d has not been scanned by any user for a long time, the AP 110 d may be expired from the map of spatial distribution of signal strengths. The AP 110 d can be restored back to the map of spatial distribution of signal strengths when the signal from the AP 110 d is re-detected by a mobile device. In particular embodiments, the access points may be relocated. The new locations information of the access points can be updated on the map of spatial distribution of signal strengths along with the new scan signal data.

In particular embodiments, by tracking the relative locations of multiple users in the environment, the system can monitor the traffic within the environment. For example, the system may be able to determine a particular location as a “hotspot” when more users are identified nearby the particular location. The system can provide this traffic information to the users, such as showing a virtual “hotspot” at the particular location for display to the users. Additionally, the virtual path created by the system leading the users to the particular location may be alternated to avoid the traffic, or the user may decide to change his destination to avoid or to follow the “hotspot”.

Additionally, in particular embodiments, depending on the mobile devices, the collected signal strengths data may be weighted differently in accordance with the trustiness of the mobile devices. For example, the first user is a registered long term member of the system while the second user is a first-time guest. The signals collected by the first user's device may be more trustworthy than the signals collected by the second user's smartphone, such that the signals scanned by the first user's device may be weight more than the signals scanned by the second user's smartphone.

In particular embodiments, the systems and methods described above can be installed in an indoor environment, such as a shopping mall, or can be installed in a defined outdoor area, such as an outdoor amusement park. The accuracy of the location identification may be affected by various factors including, but not limited to, the number of the users accessing the system, the number of the access points installed in the environment, location of the access points, the frequency of sampling signals, the device configurations, the system bandwidth, or the configuration of computation devices of the system for processing the data.

In some embodiments described herein, the systems and methods of tracking locations using AR tracking technique can correlate the identified locations with the spatial distribution of signal strengths and provide a faster and more accurate location identification mechanism. The accuracy of the locations identification can be improved significantly when the image data, spatial distribution of signal strengths, and/or motion data are combined. The crowdsourcing technique adopted in the location tracking systems and methods can further refine the location tracking results with data subsequently detected by multiple users.

FIG. 2 illustrates an example method for location tracking using AR in particular embodiments. The method 200 may begin at step 210, where a mobile computing device (e.g., a smartphone) periodically detects signals transmitted from a plurality of fixed-location signal sources (e.g., access points) within an environment, wherein the mobile computing device may comprise at least a camera. The signals detected by the mobile computing device may be transmitted to a computing system Depending on mobile device's locations, the strengths of the signals are detected differently. The closer the mobile computing device is to the fix-location signal sources, the stronger the signal strengths are detected. Thus, the distribution of signal strengths detected by the mobile computing device may be different from location to location.

At step 220, a spatial distribution of signal strengths can be determined with respect to the detected signal strengths by the computing system. The spatial distribution of signal strengths may be formed by interpolating the periodically detected distributions of the signal strengths, wherein each distribution of signal strengths associates with a sampling location at where the mobile computing device detects the signals from the fixed-location signal sources.

At step 224, a plurality of relative positions with respect to the environment of the mobile computing device is identified by the computing system using the determined spatial distribution of signal strengths. By knowing the locations of the fixed-location signal sources and the detected distribution of signal strengths, the computing system can identify the mobile computing device's location with respect to the environment.

At step 230, a plurality of images of the environment are captured by the camera of the mobile computing device. The built-in camera on the mobile computing device or an AR device can capture a plurality of images or a video comprising a plurality of image frames of the environment.

At step 240, the computing system analyzes the captured images and angles of capturing images using AR techniques, and the image analysis results is used to accurately identify the mobile device's locations. The system can analyze the images, the angles of capturing the images, or the sequence of capturing the images, and use that information to identify the relative locations of the mobile device.

At step 250, the computing system calibrates the plurality of relative positions identified in the step 224 with the image analysis results obtained in the step 240. By analyzing the captured images, the system is able to obtain space information around the mobile computing device and uses the space information to refine the plurality of relative positions. Thus, the accuracy of identification of the plurality of relative positions can be improved.

At step 260, a map of spatial distribution of signal strengths is created by correlating the spatial distribution of signal strengths determined in the step 224 with the plurality of relative locations of the mobile computing device identified and calibrated in the step 250. The map of spatial distribution of signal strengths is saved in a storage component of the computing system and updated with subsequently collected data. For a specific distribution of signal strengths, a respective location can be identified precisely and promptly on the map of spatial distribution of signal strengths.

At step 270, by the computing system, given a specific distribution of signal strengths detected by a second mobile computing device, a relative location of the second mobile computing device is identified on the map of spatial distribution of signal strengths with respect to the specific distribution of signal strengths. The distribution of signal strengths of the second mobile computing device is detected as the second user walks around the same environment and the second mobile computing device scans the same access points at the same locations in the same environment. According to the identified relative location of the second mobile computing device, an AR content is provided to the second mobile device for display.

In particular embodiments, an AR application may be configured to operate on any computing device, including mobile devices (e.g., smartphones, tablets, laptops, AR glasses, etc.) and other types of computing devices (e.g., desktop computer). Computing devices may have different hardware resources and capabilities, including, for example, CPU and/or GPU, memory, cache, storage, optical sensors, display, and any other system resources that may affect the quality of the AR effect produced by the AR application. In particular embodiments, an AR application may be configured to obtain video frames of a real-world scene captured by a camera communicatively coupled to the device on which the AR application is running. By processing the video frames, the AR application may track real-world objects captured within the video frames. In particular embodiments, the AR application may support multiple types of tracking algorithms.

FIG. 3 illustrates an example network environment 300 associated with a social-networking system in particular embodiments. Network environment 300 includes a user 301, a client system 330, a social-networking system 360, and a third-party system 370 connected to each other by a network 310. Although FIG. 3 illustrates a particular arrangement of user 301, client system 330, social-networking system 360, third-party system 370, and network 310, this disclosure contemplates any suitable arrangement of user 301, client system 330, social-networking system 360, third-party system 370, and network 310. As an example and not by way of limitation, two or more of client system 330, social-networking system 360, and third-party system 370 may be connected to each other directly, bypassing network 310. As another example, two or more of client system 330, social-networking system 360, and third-party system 370 may be physically or logically co-located with each other in whole or in part. Moreover, although FIG. 3 illustrates a particular number of users 301, client systems 330, social-networking systems 360, third-party systems 370, and networks 310, this disclosure contemplates any suitable number of users 301, client systems 330, social-networking systems 360, third-party systems 370, and networks 310. As an example and not by way of limitation, network environment 300 may include multiple users 301, client system 330, social-networking systems 360, third-party systems 370, and networks 310.

In particular embodiments, user 301 may be an individual (human user), an entity (e.g., an enterprise, business, or third-party application), or a group (e.g., of individuals or entities) that interacts or communicates with or over social-networking system 360. In particular embodiments, social-networking system 360 may be a network-addressable computing system hosting an online social network. Social-networking system 360 may generate, store, receive, and send social-networking data, such as, for example, user-profile data, concept-profile data, social-graph information, or other suitable data related to the online social network. Social-networking system 360 may be accessed by the other components of network environment 300 either directly or via network 310. In particular embodiments, social-networking system 360 may include an authorization server (or other suitable component(s)) that allows users 301 to opt in to or opt out of having their actions logged by social-networking system 360 or shared with other systems (e.g., third-party systems 370), for example, by setting appropriate privacy settings. A privacy setting of a user may determine what information associated with the user may be logged, how information associated with the user may be logged, when information associated with the user may be logged, who may log information associated with the user, whom information associated with the user may be shared with, and for what purposes information associated with the user may be logged or shared. Authorization servers may be used to enforce one or more privacy settings of the users of social-networking system 360 through blocking, data hashing, anonymization, or other suitable techniques as appropriate. In particular embodiments, third-party system 370 may be a network-addressable computing system. Third-party system 370 may generate, store, receive, and send content items, such as, for example, text, images, video, or any other content item. Third-party system 370 may be accessed by the other components of network environment 300 either directly or via network 310. In particular embodiments, one or more users 301 may use one or more client systems 330 to access, send data to, and receive data from social-networking system 360 or third-party system 370. Client system 330 may access social-networking system 360 or third-party system 370 directly, via network 310, or via a third-party system. As an example and not by way of limitation, client system 330 may access third-party system 370 via social-networking system 360. Client system 330 may be any suitable computing device, such as, for example, a personal computer, a laptop computer, a cellular telephone, a smartphone, a tablet computer, or an augmented/virtual reality device.

This disclosure contemplates any suitable network 310. As an example and not by way of limitation, one or more portions of network 310 may include an ad hoc network, an intranet, an extranet, a virtual private network (VPN), a local area network (LAN), a wireless LAN (WLAN), a wide area network (WAN), a wireless WAN (WWAN), a metropolitan area network (MAN), a portion of the Internet, a portion of the Public Switched Telephone Network (PSTN), a cellular telephone network, or a combination of two or more of these. Network 310 may include one or more networks 310.

Links 350 may connect client system 330, social-networking system 360, and third-party system 370 to communication network 310 or to each other. This disclosure contemplates any suitable links 350. In particular embodiments, one or more links 350 include one or more wireline (such as for example Digital Subscriber Line (DSL) or Data Over Cable Service Interface Specification (DOCSIS)), wireless (such as for example Wi-Fi or Worldwide Interoperability for Microwave Access (WiMAX)), or optical (such as for example Synchronous Optical Network (SONET) or Synchronous Digital Hierarchy (SDH)) links. In particular embodiments, one or more links 350 each include an ad hoc network, an intranet, an extranet, a VPN, a LAN, a WLAN, a WAN, a WWAN, a MAN, a portion of the Internet, a portion of the PSTN, a cellular technology-based network, a satellite communications technology-based network, another link 350, or a combination of two or more such links 350. Links 350 need not necessarily be the same throughout network environment 300. One or more first links 350 may differ in one or more respects from one or more second links 350.

FIG. 4 illustrates example social graph 400 in particular embodiments. In particular embodiments, social-networking system 360 may store one or more social graphs 400 in one or more data stores. In particular embodiments, social graph 400 may include multiple nodes—which may include multiple user nodes 402 or multiple concept nodes 404—and multiple edges 406 connecting the nodes. Example social graph 400 illustrated in FIG. 4 is shown, for didactic purposes, in a two-dimensional visual map representation. In particular embodiments, a social-networking system 360, client system 330, or third-party system 370 may access social graph 400 and related social-graph information for suitable applications. The nodes and edges of social graph 400 may be stored as data objects, for example, in a data store (such as a social-graph database). Such a data store may include one or more searchable or queryable indexes of nodes or edges of social graph 400.

In particular embodiments, a user node 402 may correspond to a user of social-networking system 360. As an example and not by way of limitation, a user may be an individual (human user), an entity (e.g., an enterprise, business, or third-party application), or a group (e.g., of individuals or entities) that interacts or communicates with or over social-networking system 360. In particular embodiments, when a user registers for an account with social-networking system 360, social-networking system 360 may create a user node 402 corresponding to the user and store the user node 402 in one or more data stores. Users and user nodes 402 described herein may, where appropriate, refer to registered users and user nodes 402 associated with registered users. In addition or as an alternative, users and user nodes 402 described herein may, where appropriate, refer to users that have not registered with social-networking system 360. In particular embodiments, a user node 402 may be associated with information provided by a user or information gathered by various systems, including social-networking system 360. As an example and not by way of limitation, a user may provide his or her name, profile picture, contact information, birth date, sex, marital status, family status, employment, education background, preferences, interests, or other demographic information. In particular embodiments, a user node 402 may be associated with one or more data objects corresponding to information associated with a user. In particular embodiments, a user node 402 may correspond to one or more webpages.

In particular embodiments, a concept node 404 may correspond to a concept. As an example and not by way of limitation, a concept may correspond to a place (such as, for example, a movie theater, restaurant, landmark, or city); a website (such as, for example, a website associated with social-network system 360 or a third-party website associated with a web-application server); an entity (such as, for example, a person, business, group, sports team, or celebrity); a resource (such as, for example, an audio file, video file, digital photo, text file, structured document, or application) which may be located within social-networking system 360 or on an external server, such as a web-application server; real or intellectual property (such as, for example, a sculpture, painting, movie, game, song, idea, photograph, or written work); a game; an activity; an idea or theory; an object in a augmented/virtual reality environment; another suitable concept; or two or more such concepts. A concept node 404 may be associated with information of a concept provided by a user or information gathered by various systems, including social-networking system 360. As an example and not by way of limitation, information of a concept may include a name or a title; one or more images (e.g., an image of the cover page of a book); a location (e.g., an address or a geographical location); a website (which may be associated with a URL); contact information (e.g., a phone number or an email address); other suitable concept information; or any suitable combination of such information. In particular embodiments, a concept node 404 may be associated with one or more data objects corresponding to information associated with concept node 404. In particular embodiments, a concept node 404 may correspond to one or more webpages.

In particular embodiments, a node in social graph 400 may represent or be represented by a webpage (which may be referred to as a “profile page”). Profile pages may be hosted by or accessible to social-networking system 360. Profile pages may also be hosted on third-party websites associated with a third-party server 370. As an example and not by way of limitation, a profile page corresponding to a particular external webpage may be the particular external webpage and the profile page may correspond to a particular concept node 404. Profile pages may be viewable by all or a selected subset of other users. As an example and not by way of limitation, a user node 402 may have a corresponding user-profile page in which the corresponding user may add content, make declarations, or otherwise express himself or herself. As another example and not by way of limitation, a concept node 404 may have a corresponding concept-profile page in which one or more users may add content, make declarations, or express themselves, particularly in relation to the concept corresponding to concept node 404.

In particular embodiments, a concept node 404 may represent a third-party webpage or resource hosted by a third-party system 370. The third-party webpage or resource may include, among other elements, content, a selectable or other icon, or other inter-actable object (which may be implemented, for example, in JavaScript, AJAX, or PHP codes) representing an action or activity. As an example and not by way of limitation, a third-party webpage may include a selectable icon such as “like,” “check-in,” “eat,” “recommend,” or another suitable action or activity. A user viewing the third-party webpage may perform an action by selecting one of the icons (e.g., “check-in”), causing a client system 330 to send to social-networking system 360 a message indicating the user's action. In response to the message, social-networking system 360 may create an edge (e.g., a check-in-type edge) between a user node 402 corresponding to the user and a concept node 404 corresponding to the third-party webpage or resource and store edge 406 in one or more data stores.

In particular embodiments, a pair of nodes in social graph 400 may be connected to each other by one or more edges 406. An edge 406 connecting a pair of nodes may represent a relationship between the pair of nodes. In particular embodiments, an edge 406 may include or represent one or more data objects or attributes corresponding to the relationship between a pair of nodes. As an example and not by way of limitation, a first user may indicate that a second user is a “friend” of the first user. In response to this indication, social-networking system 360 may send a “friend request” to the second user. If the second user confirms the “friend request,” social-networking system 360 may create an edge 406 connecting the first user's user node 402 to the second user's user node 402 in social graph 400 and store edge 406 as social-graph information in one or more of data stores. In the example of FIG. 4, social graph 400 includes an edge 406 indicating a friend relation between user nodes 402 of user “A” and user “B” and an edge indicating a friend relation between user nodes 402 of user “C” and user “B.” Although this disclosure describes or illustrates particular edges 406 with particular attributes connecting particular user nodes 402, this disclosure contemplates any suitable edges 406 with any suitable attributes connecting user nodes 402. As an example and not by way of limitation, an edge 406 may represent a friendship, family relationship, business or employment relationship, fan relationship (including, e.g., liking, etc.), follower relationship, visitor relationship (including, e.g., accessing, viewing, checking-in, sharing, etc.), subscriber relationship, superior/subordinate relationship, reciprocal relationship, non-reciprocal relationship, another suitable type of relationship, or two or more such relationships. Moreover, although this disclosure generally describes nodes as being connected, this disclosure also describes users or concepts as being connected. Herein, references to users or concepts being connected may, where appropriate, refer to the nodes corresponding to those users or concepts being connected in social graph 400 by one or more edges 406.

In particular embodiments, an edge 406 between a user node 402 and a concept node 404 may represent a particular action or activity performed by a user associated with user node 402 toward a concept associated with a concept node 404. As an example and not by way of limitation, as illustrated in FIG. 4, a user may “like,” “attended,” “played,” “listened,” “cooked,” “worked at,” or “watched” a concept, each of which may correspond to an edge type or subtype. A concept-profile page corresponding to a concept node 404 may include, for example, a selectable “check in” icon (such as, for example, a clickable “check in” icon) or a selectable “add to favorites” icon. Similarly, after a user clicks these icons, social-networking system 360 may create a “favorite” edge or a “check in” edge in response to a user's action corresponding to a respective action. As another example and not by way of limitation, a user (user “C”) may listen to a particular song (“Imagine”) using a particular application (an online music application). In this case, social-networking system 360 may create a “listened” edge 406 and a “used” edge (as illustrated in FIG. 4) between user nodes 402 corresponding to the user and concept nodes 404 corresponding to the song and application to indicate that the user listened to the song and used the application. Moreover, social-networking system 360 may create a “played” edge 406 (as illustrated in FIG. 4) between concept nodes 404 corresponding to the song and the application to indicate that the particular song was played by the particular application. In this case, “played” edge 406 corresponds to an action performed by an external application on an external audio file (the song “Imagine”). Although this disclosure describes particular edges 406 with particular attributes connecting user nodes 402 and concept nodes 404, this disclosure contemplates any suitable edges 406 with any suitable attributes connecting user nodes 402 and concept nodes 404. Moreover, although this disclosure describes edges between a user node 402 and a concept node 404 representing a single relationship, this disclosure contemplates edges between a user node 402 and a concept node 404 representing one or more relationships. As an example and not by way of limitation, an edge 406 may represent both that a user likes and has used at a particular concept. Alternatively, another edge 406 may represent each type of relationship (or multiples of a single relationship) between a user node 402 and a concept node 404 (as illustrated in FIG. 4 between user node 402 for user “E” and concept node 404).

In particular embodiments, social-networking system 360 may create an edge 406 between a user node 402 and a concept node 404 in social graph 400. As an example and not by way of limitation, a user viewing a concept-profile page (such as, for example, by using a web browser or a special-purpose application hosted by the user's client system 330) may indicate that he or she likes the concept represented by the concept node 404 by clicking or selecting a “Like” icon, which may cause the user's client system 330 to send to social-networking system 360 a message indicating the user's liking of the concept associated with the concept-profile page. In response to the message, social-networking system 360 may create an edge 406 between user node 402 associated with the user and concept node 404, as illustrated by “like” edge 406 between the user and concept node 404. In particular embodiments, social-networking system 360 may store an edge 406 in one or more data stores. In particular embodiments, an edge 406 may be automatically formed by social-networking system 360 in response to a particular user action. As an example and not by way of limitation, if a first user uploads a picture, watches a movie, or listens to a song, an edge 406 may be formed between user node 402 corresponding to the first user and concept nodes 404 corresponding to those concepts. Although this disclosure describes forming particular edges 406 in particular manners, this disclosure contemplates forming any suitable edges 406 in any suitable manner.

In particular embodiments, an advertisement may be text (which may be HTML-linked), one or more images (which may be HTML-linked), one or more videos, audio, other suitable digital object files, a suitable combination of these, or any other suitable advertisement in any suitable digital format presented on one or more web pages, in one or more e-mails, or in connection with search results requested by a user. In addition or as an alternative, an advertisement may be one or more sponsored stories (e.g., a news-feed or ticker item on social-networking system 360). A sponsored story may be a social action by a user (such as “liking” a page, “liking” or commenting on a post on a page, RSVPing to an event associated with a page, voting on a question posted on a page, checking in to a place, using an application or playing a game, or “liking” or sharing a website) that an advertiser promotes, for example, by having the social action presented within a pre-determined area of a profile page of a user or other page, presented with additional information associated with the advertiser, bumped up or otherwise highlighted within news feeds or tickers of other users, or otherwise promoted. The advertiser may pay to have the social action promoted. The social action may be promoted within or on social-networking system 360. In addition or as an alternative, the social action may be promoted outside or off of social-networking system 360, where appropriate. In particular embodiments, a page may be an on-line presence (such as a webpage or website within or outside of social-networking system 360) of a business, organization, or brand facilitating its sharing of stories and connecting with people. A page may be customized, for example, by adding applications, posting stories, or hosting events.

A sponsored story may be generated from stories in users' news feeds and promoted to specific areas within displays of users' web browsers when viewing a web page associated with social-networking system 360. Sponsored stories are more likely to be viewed by users, at least in part because sponsored stories generally involve interactions or suggestions by the users' friends, fan pages, or other connections. In connection with sponsored stories, particular embodiments may utilize one or more systems, components, elements, functions, methods, operations, or steps disclosed in U.S. patent application Ser. No. 13/327,557, entitled “Sponsored Stories Unit Creation from Organic Activity Stream” and filed 15 Dec. 2011, U.S. Patent Application Publication No. 2012/0203831, entitled “Sponsored Stories Unit Creation from Organic Activity Stream” and filed 3 Feb. 2012 as U.S. patent application Ser. No. 13/020,745, or U.S. Patent Application Publication No. 2012/0233009, entitled “Endorsement Subscriptions for Sponsored Stories” and filed 9 Mar. 2011 as U.S. patent application Ser. No. 13/044,506, which are all incorporated herein by reference as an example and not by way of limitation. In particular embodiments, sponsored stories may utilize computer-vision algorithms to detect products in uploaded images or photos lacking an explicit connection to an advertiser as disclosed in U.S. patent application Ser. No. 13/212,356, entitled “Computer-Vision Content Detection for Sponsored Stories” and filed 18 Aug. 2011, which is incorporated herein by reference as an example and not by way of limitation.

As described above, an advertisement may be text (which may be HTML-linked), one or more images (which may be HTML-linked), one or more videos, audio, one or more ADOBE FLASH files, a suitable combination of these, or any other suitable advertisement in any suitable digital format. In particular embodiments, an advertisement may be requested for display within third-party webpages, social-networking-system webpages, or other pages. An advertisement may be displayed in a dedicated portion of a page, such as in a banner area at the top of the page, in a column at the side of the page, in a GUI of the page, in a pop-up window, over the top of content of the page, or elsewhere with respect to the page. In addition or as an alternative, an advertisement may be displayed within an application or within a game. An advertisement may be displayed within dedicated pages, requiring the user to interact with or watch the advertisement before the user may access a page, utilize an application, or play a game. The user may, for example view the advertisement through a web browser.

A user may interact with an advertisement in any suitable manner. The user may click or otherwise select the advertisement, and the advertisement may direct the user (or a browser or other application being used by the user) to a page associated with the advertisement. At the page associated with the advertisement, the user may take additional actions, such as purchasing a product or service associated with the advertisement, receiving information associated with the advertisement, or subscribing to a newsletter associated with the advertisement. An advertisement with audio or video may be played by selecting a component of the advertisement (like a “play button”). In particular embodiments, an advertisement may include one or more games, which a user or other application may play in connection with the advertisement. An advertisement may include functionality for responding to a poll or question in the advertisement.

An advertisement may include social-networking-system functionality that a user may interact with. For example, an advertisement may enable a user to “like” or otherwise endorse the advertisement by selecting an icon or link associated with endorsement. Similarly, a user may share the advertisement with another user (e.g., through social-networking system 360) or RSVP (e.g., through social-networking system 360) to an event associated with the advertisement. In addition or as an alternative, an advertisement may include social-networking-system content directed to the user. For example, an advertisement may display information about a friend of the user within social-networking system 360 who has taken an action associated with the subject matter of the advertisement.

Social-networking-system functionality or content may be associated with an advertisement in any suitable manner. For example, an advertising system (which may include hardware, software, or both for receiving bids for advertisements and selecting advertisements in response) may retrieve social-networking functionality or content from social-networking system 360 and incorporate the retrieved social-networking functionality or content into the advertisement before serving the advertisement to a user. Examples of selecting and providing social-networking-system functionality or content with an advertisement are disclosed in U.S. Patent Application Publication No. 2012/0084160, entitled “Providing Social Endorsements with Online Advertising” and filed 5 Oct. 2010 as U.S. patent application Ser. No. 12/898,662, and in U.S. Patent Application Publication No. 2012/0232998, entitled “Selecting Social Endorsement Information for an Advertisement for Display to a Viewing User” and filed 8 Mar. 2011 as U.S. patent application Ser. No. 13/043,424, which are both incorporated herein by reference as examples only and not by way of limitation. Interacting with an advertisement that is associated with social-networking-system functionality or content may cause information about the interaction to be displayed in a profile page of the user in social-networking-system 360.

Particular embodiments may facilitate the delivery of advertisements to users that are more likely to find the advertisements more relevant or useful. For example, an advertiser may realize higher conversion rates (and therefore higher return on investment (ROI) from advertising) by identifying and targeting users that are more likely to find its advertisements more relevant or useful. The advertiser may use user-profile information in social-networking system 360 to identify those users. In addition or as an alternative, social-networking system 360 may use user-profile information in social-networking system 360 to identify those users for the advertiser. As examples and not by way of limitation, particular embodiments may target users with the following: invitations or suggestions of events; suggestions regarding coupons, deals, or wish-list items; suggestions regarding friends' life events; suggestions regarding groups; advertisements; or social advertisements. Such targeting may occur, where appropriate, on or within social-networking system 360, off or outside of social-networking system 360, or on mobile computing devices of users. When on or within social-networking system 360, such targeting may be directed to users' news feeds, search results, e-mail or other in-boxes, or notifications channels or may appear in particular area of web pages of social-networking system 360, such as a right-hand side of a web page in a concierge or grouper area (which may group along a right-hand rail advertisements associated with the same concept, node, or object) or a network-ego area (which may be based on what a user is viewing on the web page and a current news feed of the user). When off or outside of social-networking system 360, such targeting may be provided through a third-party website, e.g., involving an ad exchange or a social plug-in. When on a mobile computing device of a user, such targeting may be provided through push notifications to the mobile computing device.

Targeting criteria used to identify and target users may include explicit, stated user interests on social-networking system 360 or explicit connections of a user to a node, object, entity, brand, or page on social-networking system 360. In addition or as an alternative, such targeting criteria may include implicit or inferred user interests or connections (which may include analyzing a user's history, demographic, social or other activities, friends' social or other activities, subscriptions, or any of the preceding of other users similar to the user (based, e.g., on shared interests, connections, or events)). Particular embodiments may utilize platform targeting, which may involve platform and “like” impression data; contextual signals; light-weight connections (e.g., “check-ins”); connection lookalikes; fans; extracted keywords; EMU advertising; inferential advertising; coefficients, affinities, or other social-graph information; friends-of-friends connections; pinning or boosting; deals; polls; household income, social clusters or groups; products detected in images or other media; social- or open-graph edge types; geo-prediction; views of profile or pages; status updates or other user posts (analysis of which may involve natural-language processing or keyword extraction); events information; or collaborative filtering. Identifying and targeting users may also include privacy settings (such as user opt-outs), data hashing, or data anonymization, as appropriate.

To target users with advertisements, particular embodiments may utilize one or more systems, components, elements, functions, methods, operations, or steps disclosed in the following, which are all incorporated herein by reference as examples and not by way of limitation: U.S. Patent Application Publication No. 2009/0119167, entitled “Social Advertisements and Other Informational Messages on a Social Networking Website and Advertising Model for Same” and filed 18 Aug. 2008 as U.S. patent application Ser. No. 12/193,702; U.S. Patent Application Publication No. 2009/0070219, entitled “Targeting Advertisements in a Social Network” and filed 20 Aug. 2008 as U.S. patent application Ser. No. 12/195,321; U.S. Patent Application Publication No. 2012/0158501, entitled “Targeting Social Advertising to Friends of Users Who Have Interacted With an Object Associated with the Advertising” and filed 15 Dec. 2010 as U.S. patent application Ser. No. 12/968,786; or U.S. Patent Application Publication No. 2012/0166532, entitled “Contextually Relevant Affinity Prediction in a Social-Networking System” and filed 23 Dec. 2010 as U.S. patent application Ser. No. 12/978,265.

An advertisement may be presented or otherwise delivered using plug-ins for web browsers or other applications, iframe elements, news feeds, tickers, notifications (which may include, for example, e-mail, Short Message Service (SMS) messages, or notifications), or other means. An advertisement may be presented or otherwise delivered to a user on a mobile or other computing device of the user. In connection with delivering advertisements, particular embodiments may utilize one or more systems, components, elements, functions, methods, operations, or steps disclosed in the following, which are all incorporated herein by reference as examples and not by way of limitation: U.S. Patent Application Publication No. 2012/0159635, entitled “Comment Plug-In for Third-Party System” and filed 15 Dec. 2010 as U.S. patent application Ser. No. 12/969,368; U.S. Patent Application Publication No. 2012/0158753, entitled “Comment Ordering System” and filed 15 Dec. 2010 as U.S. patent application Ser. No. 12/969,408; U.S. Pat. No. 7,669,123, entitled “Dynamically Providing a News Feed About a User of a Social Network” and filed 11 Aug. 2006 as U.S. patent application Ser. No. 11/503,242; U.S. Pat. No. 8,402,094, entitled “Providing a Newsfeed Based on User Affinity for Entities and Monitored Actions in a Social Network Environment” and filed 11 Aug. 2006 as U.S. patent application Ser. No. 11/503,093; U.S. Patent Application Publication No. 2012/0072428, entitled “Action Clustering for News Feeds” and filed 16 Sep. 2010 as U.S. patent application Ser. No. 12/884,010; U.S. Patent Application Publication No. 2011/0004692, entitled “Gathering Information about Connections in a Social Networking Service” and filed 1 Jul. 2009 as U.S. patent application Ser. No. 12/496,606; U.S. Patent Application Publication No. 2008/0065701, entitled “Method and System for Tracking Changes to User Content in an Online Social Network” and filed 12 Sep. 2006 as U.S. patent application Ser. No. 11/531,154; U.S. Patent Application Publication No. 2008/0065604, entitled “Feeding Updates to Landing Pages of Users of an Online Social Network from External Sources” and filed 17 Jan. 2007 as U.S. patent application Ser. No. 11/624,088; U.S. Pat. No. 8,244,848, entitled “Integrated Social-Network Environment” and filed 19 Apr. 2010 as U.S. patent application Ser. No. 12/763,171; U.S. Patent Application Publication No. 2011/0083101, entitled “Sharing of Location-Based Content Item in Social-Networking Service” and filed 6 Oct. 2009 as U.S. patent application Ser. No. 12/574,614; U.S. Pat. No. 8,150,844, entitled “Location Ranking Using Social-Graph Information” and filed 18 Aug. 2010 as U.S. patent application Ser. No. 12/858,718; U.S. patent application Ser. No. 13/051,286, entitled “Sending Notifications to Users Based on Users' Notification Tolerance Levels” and filed 18 Mar. 2011; U.S. patent application Ser. No. 13/096,184, entitled “Managing Notifications Pushed to Mobile devices” and filed 28 Apr. 2011; U.S. patent application Ser. No. 13/276,248, entitled “Platform-Specific Notification Delivery Channel” and filed 18 Oct. 2011; or U.S. Patent Application Publication No. 2012/0197709, entitled “Mobile Advertisement with Social Component for Geo-Social Networking System” and filed 1 Feb. 2011 as U.S. patent application Ser. No. 13/019,061. Although this disclosure describes or illustrates particular advertisements being delivered in particular ways and in connection with particular content, this disclosure contemplates any suitable advertisements delivered in any suitable ways and in connection with any suitable content.

In particular embodiments, social-networking system 360 may determine the social-graph affinity (which may be referred to herein as “affinity”) of various social-graph entities for each other. Affinity may represent the strength of a relationship or level of interest between particular objects associated with the online social network, such as users, concepts, content, actions, advertisements, other objects associated with the online social network, or any suitable combination thereof. Affinity may also be determined with respect to objects associated with third-party systems 370 or other suitable systems. An overall affinity for a social-graph entity for each user, subject matter, or type of content may be established. The overall affinity may change based on continued monitoring of the actions or relationships associated with the social-graph entity. Although this disclosure describes determining particular affinities in a particular manner, this disclosure contemplates determining any suitable affinities in any suitable manner.

In particular embodiments, social-networking system 360 may measure or quantify social-graph affinity using an affinity coefficient (which may be referred to herein as “coefficient”). The coefficient may represent or quantify the strength of a relationship between particular objects associated with the online social network. The coefficient may also represent a probability or function that measures a predicted probability that a user will perform a particular action based on the user's interest in the action. In this way, a user's future actions may be predicted based on the user's prior actions, where the coefficient may be calculated at least in part on the history of the user's actions. Coefficients may be used to predict any number of actions, which may be within or outside of the online social network. As an example and not by way of limitation, these actions may include various types of communications, such as sending messages, posting content, or commenting on content; various types of an observation actions, such as accessing or viewing profile pages, media, or other suitable content; various types of coincidence information about two or more social-graph entities, such as being in the same group, tagged in the same photograph, checked-in at the same location, or attending the same event; or other suitable actions. Although this disclosure describes measuring affinity in a particular manner, this disclosure contemplates measuring affinity in any suitable manner.

In particular embodiments, social-networking system 360 may use a variety of factors to calculate a coefficient. These factors may include, for example, user actions, types of relationships between objects, location information, other suitable factors, or any combination thereof. In particular embodiments, different factors may be weighted differently when calculating the coefficient. The weights for each factor may be static or the weights may change according to, for example, the user, the type of relationship, the type of action, the user's location, and so forth. Ratings for the factors may be combined according to their weights to determine an overall coefficient for the user. As an example and not by way of limitation, particular user actions may be assigned both a rating and a weight while a relationship associated with the particular user action is assigned a rating and a correlating weight (e.g., so the weights total 100%). To calculate the coefficient of a user towards a particular object, the rating assigned to the user's actions may comprise, for example, 60% of the overall coefficient, while the relationship between the user and the object may comprise 40% of the overall coefficient. In particular embodiments, the social-networking system 360 may consider a variety of variables when determining weights for various factors used to calculate a coefficient, such as, for example, the time since information was accessed, decay factors, frequency of access, relationship to information or relationship to the object about which information was accessed, relationship to social-graph entities connected to the object, short- or long-term averages of user actions, user feedback, other suitable variables, or any combination thereof. As an example and not by way of limitation, a coefficient may include a decay factor that causes the strength of the signal provided by particular actions to decay with time, such that more recent actions are more relevant when calculating the coefficient. The ratings and weights may be continuously updated based on continued tracking of the actions upon which the coefficient is based. Any type of process or algorithm may be employed for assigning, combining, averaging, and so forth the ratings for each factor and the weights assigned to the factors. In particular embodiments, social-networking system 360 may determine coefficients using machine-learning algorithms trained on historical actions and past user responses, or data farmed from users by exposing them to various options and measuring responses. Although this disclosure describes calculating coefficients in a particular manner, this disclosure contemplates calculating coefficients in any suitable manner.

In particular embodiments, social-networking system 360 may calculate a coefficient based on a user's actions. Social-networking system 360 may monitor such actions on the online social network, on a third-party system 370, on other suitable systems, or any combination thereof. Any suitable type of user actions may be tracked or monitored. Typical user actions include viewing profile pages, creating or posting content, interacting with content, tagging or being tagged in images, joining groups, listing and confirming attendance at events, checking-in at locations, liking particular pages, creating pages, and performing other tasks that facilitate social action. In particular embodiments, social-networking system 360 may calculate a coefficient based on the user's actions with particular types of content. The content may be associated with the online social network, a third-party system 370, or another suitable system. The content may include users, profile pages, posts, news stories, headlines, instant messages, chat room conversations, emails, advertisements, pictures, video, music, other suitable objects, or any combination thereof. Social-networking system 360 may analyze a user's actions to determine whether one or more of the actions indicate an affinity for subject matter, content, other users, and so forth. As an example and not by way of limitation, if a user may make frequently posts content related to “coffee” or variants thereof, social-networking system 360 may determine the user has a high coefficient with respect to the concept “coffee”. Particular actions or types of actions may be assigned a higher weight and/or rating than other actions, which may affect the overall calculated coefficient. As an example and not by way of limitation, if a first user emails a second user, the weight or the rating for the action may be higher than if the first user simply views the user-profile page for the second user.

In particular embodiments, social-networking system 360 may calculate a coefficient based on the type of relationship between particular objects. Referencing the social graph 400, social-networking system 360 may analyze the number and/or type of edges 406 connecting particular user nodes 402 and concept nodes 404 when calculating a coefficient. As an example and not by way of limitation, user nodes 402 that are connected by a spouse-type edge (representing that the two users are married) may be assigned a higher coefficient than a user node 402 that are connected by a friend-type edge. In other words, depending upon the weights assigned to the actions and relationships for the particular user, the overall affinity may be determined to be higher for content about the user's spouse than for content about the user's friend. In particular embodiments, the relationships a user has with another object may affect the weights and/or the ratings of the user's actions with respect to calculating the coefficient for that object. As an example and not by way of limitation, if a user is tagged in first photo, but merely likes a second photo, social-networking system 360 may determine that the user has a higher coefficient with respect to the first photo than the second photo because having a tagged-in-type relationship with content may be assigned a higher weight and/or rating than having a like-type relationship with content. In particular embodiments, social-networking system 360 may calculate a coefficient for a first user based on the relationship one or more second users have with a particular object. In other words, the connections and coefficients other users have with an object may affect the first user's coefficient for the object. As an example and not by way of limitation, if a first user is connected to or has a high coefficient for one or more second users, and those second users are connected to or have a high coefficient for a particular object, social-networking system 360 may determine that the first user should also have a relatively high coefficient for the particular object. In particular embodiments, the coefficient may be based on the degree of separation between particular objects. The lower coefficient may represent the decreasing likelihood that the first user will share an interest in content objects of the user that is indirectly connected to the first user in the social graph 400. As an example and not by way of limitation, social-graph entities that are closer in the social graph 400 (i.e., fewer degrees of separation) may have a higher coefficient than entities that are further apart in the social graph 400.

In particular embodiments, social-networking system 360 may calculate a coefficient based on location information. Objects that are geographically closer to each other may be considered to be more related or of more interest to each other than more distant objects. In particular embodiments, the coefficient of a user towards a particular object may be based on the proximity of the object's location to a current location associated with the user (or the location of a client system 330 of the user). A first user may be more interested in other users or concepts that are closer to the first user. As an example and not by way of limitation, if a user is one mile from an airport and two miles from a gas station, social-networking system 360 may determine that the user has a higher coefficient for the airport than the gas station based on the proximity of the airport to the user.

In particular embodiments, social-networking system 360 may perform particular actions with respect to a user based on coefficient information. Coefficients may be used to predict whether a user will perform a particular action based on the user's interest in the action. A coefficient may be used when generating or presenting any type of objects to a user, such as advertisements, search results, news stories, media, messages, notifications, or other suitable objects. The coefficient may also be utilized to rank and order such objects, as appropriate. In this way, social-networking system 360 may provide information that is relevant to user's interests and current circumstances, increasing the likelihood that they will find such information of interest. In particular embodiments, social-networking system 360 may generate content based on coefficient information. Content objects may be provided or selected based on coefficients specific to a user. As an example and not by way of limitation, the coefficient may be used to generate media for the user, where the user may be presented with media for which the user has a high overall coefficient with respect to the media object. As another example and not by way of limitation, the coefficient may be used to generate advertisements for the user, where the user may be presented with advertisements for which the user has a high overall coefficient with respect to the advertised object. In particular embodiments, social-networking system 360 may generate search results based on coefficient information. Search results for a particular user may be scored or ranked based on the coefficient associated with the search results with respect to the querying user. As an example and not by way of limitation, search results corresponding to objects with higher coefficients may be ranked higher on a search-results page than results corresponding to objects having lower coefficients.

In particular embodiments, social-networking system 360 may calculate a coefficient in response to a request for a coefficient from a particular system or process. To predict the likely actions a user may take (or may be the subject of) in a given situation, any process may request a calculated coefficient for a user. The request may also include a set of weights to use for various factors used to calculate the coefficient. This request may come from a process running on the online social network, from a third-party system 370 (e.g., via an API or other communication channel), or from another suitable system. In response to the request, social-networking system 360 may calculate the coefficient (or access the coefficient information if it has previously been calculated and stored). In particular embodiments, social-networking system 360 may measure an affinity with respect to a particular process. Different processes (both internal and external to the online social network) may request a coefficient for a particular object or set of objects. Social-networking system 360 may provide a measure of affinity that is relevant to the particular process that requested the measure of affinity. In this way, each process receives a measure of affinity that is tailored for the different context in which the process will use the measure of affinity.

In connection with social-graph affinity and affinity coefficients, particular embodiments may utilize one or more systems, components, elements, functions, methods, operations, or steps disclosed in U.S. patent application Ser. No. 11/503,093, filed 11 Aug. 2006, U.S. patent application Ser. No. 12/977,027, filed 22 Dec. 2010, U.S. patent application Ser. No. 12/978,265, filed 23 Dec. 2010, and U.S. patent application Ser. No. 13/632,869, filed 1 Oct. 2012, each of which is incorporated by reference.

In particular embodiments, one or more of the content objects of the online social network may be associated with a privacy setting. The privacy settings (or “access settings”) for an object may be stored in any suitable manner, such as, for example, in association with the object, in an index on an authorization server, in another suitable manner, or any combination thereof. A privacy setting of an object may specify how the object (or particular information associated with an object) can be accessed (e.g., viewed or shared) using the online social network. Where the privacy settings for an object allow a particular user to access that object, the object may be described as being “visible” with respect to that user. As an example and not by way of limitation, a user of the online social network may specify privacy settings for a user-profile page that identify a set of users that may access the work experience information on the user-profile page, thus excluding other users from accessing the information. In particular embodiments, the privacy settings may specify a “blocked list” of users that should not be allowed to access certain information associated with the object. In other words, the blocked list may specify one or more users or entities for which an object is not visible. As an example and not by way of limitation, a user may specify a set of users that may not access photos albums associated with the user, thus excluding those users from accessing the photo albums (while also possibly allowing certain users not within the set of users to access the photo albums). In particular embodiments, privacy settings may be associated with particular social-graph elements. Privacy settings of a social-graph element, such as a node or an edge, may specify how the social-graph element, information associated with the social-graph element, or content objects associated with the social-graph element can be accessed using the online social network. As an example and not by way of limitation, a particular concept node 404 corresponding to a particular photo may have a privacy setting specifying that the photo may only be accessed by users tagged in the photo and their friends. In particular embodiments, privacy settings may allow users to opt in or opt out of having their actions logged by social-networking system 360 or shared with other systems (e.g., third-party system 370). In particular embodiments, the privacy settings associated with an object may specify any suitable granularity of permitted access or denial of access. As an example and not by way of limitation, access or denial of access may be specified for particular users (e.g., only me, my roommates, and my boss), users within a particular degrees-of-separation (e.g., friends, or friends-of-friends), user groups (e.g., the gaming club, my family), user networks (e.g., employees of particular employers, students or alumni of particular university), all users (“public”), no users (“private”), users of third-party systems 370, particular applications (e.g., third-party applications, external websites), other suitable users or entities, or any combination thereof. Although this disclosure describes using particular privacy settings in a particular manner, this disclosure contemplates using any suitable privacy settings in any suitable manner.

In particular embodiments, one or more servers of the social-networking system 360 may be authorization/privacy servers for enforcing privacy settings. In response to a request from a user (or other entity) for a particular object stored in a data store, social-networking system 360 may send a request to the data store for the object. The request may identify the user associated with the request and may only be sent to the user (or a client system 330 of the user) if the authorization server determines that the user is authorized to access the object based on the privacy settings associated with the object. If the requesting user is not authorized to access the object, the authorization server may prevent the requested object from being retrieved from the data store or may prevent the requested object from be sent to the user. In the search query context, an object may only be generated as a search result if the querying user is authorized to access the object. In other words, the object must have a visibility that is visible to the querying user. If the object has a visibility that is not visible to the user, the object may be excluded from the search results. Although this disclosure describes enforcing privacy settings in a particular manner, this disclosure contemplates enforcing privacy settings in any suitable manner.

In particular embodiments, one or more objects (e.g., content or other types of objects) of a computing system may be associated with one or more privacy settings. The one or more objects may be stored on or otherwise associated with any suitable computing system or application, such as, for example, a social-networking system 360, a client system 330, a third-party system 370, a social-networking application, a messaging application, a photo-sharing application, or any other suitable computing system or application. Although the examples discussed herein are in the context of an online social network, these privacy settings may be applied to any other suitable computing system. Privacy settings (or “access settings”) for an object may be stored in any suitable manner, such as, for example, in association with the object, in an index on an authorization server, in another suitable manner, or any suitable combination thereof. A privacy setting for an object may specify how the object (or particular information associated with the object) can be accessed, stored, or otherwise used (e.g., viewed, shared, modified, copied, executed, surfaced, or identified) within the online social network. When privacy settings for an object allow a particular user or other entity to access that object, the object may be described as being “visible” with respect to that user or other entity. As an example and not by way of limitation, a user of the online social network may specify privacy settings for a user-profile page that identify a set of users that may access work-experience information on the user-profile page, thus excluding other users from accessing that information.

In particular embodiments, privacy settings for an object may specify a “blocked list” of users or other entities that should not be allowed to access certain information associated with the object. In particular embodiments, the blocked list may include third-party entities. The blocked list may specify one or more users or entities for which an object is not visible. As an example and not by way of limitation, a user may specify a set of users who may not access photo albums associated with the user, thus excluding those users from accessing the photo albums (while also possibly allowing certain users not within the specified set of users to access the photo albums). In particular embodiments, privacy settings may be associated with particular social-graph elements. Privacy settings of a social-graph element, such as a node or an edge, may specify how the social-graph element, information associated with the social-graph element, or objects associated with the social-graph element can be accessed using the online social network. As an example and not by way of limitation, a particular concept node 404 corresponding to a particular photo may have a privacy setting specifying that the photo may be accessed only by users tagged in the photo and friends of the users tagged in the photo. In particular embodiments, privacy settings may allow users to opt in to or opt out of having their content, information, or actions stored/logged by the social-networking system 360 or shared with other systems (e.g., a third-party system 370). Although this disclosure describes using particular privacy settings in a particular manner, this disclosure contemplates using any suitable privacy settings in any suitable manner.

In particular embodiments, privacy settings may be based on one or more nodes or edges of a social graph 400. A privacy setting may be specified for one or more edges 406 or edge-types of the social graph 400, or with respect to one or more nodes 402, 204 or node-types of the social graph 400. The privacy settings applied to a particular edge 406 connecting two nodes may control whether the relationship between the two entities corresponding to the nodes is visible to other users of the online social network. Similarly, the privacy settings applied to a particular node may control whether the user or concept corresponding to the node is visible to other users of the online social network. As an example and not by way of limitation, a first user may share an object to the social-networking system 360. The object may be associated with a concept node 404 connected to a user node 402 of the first user by an edge 406. The first user may specify privacy settings that apply to a particular edge 406 connecting to the concept node 404 of the object or may specify privacy settings that apply to all edges 406 connecting to the concept node 404. As another example and not by way of limitation, the first user may share a set of objects of a particular object-type (e.g., a set of images). The first user may specify privacy settings with respect to all objects associated with the first user of that particular object-type as having a particular privacy setting (e.g., specifying that all images posted by the first user are visible only to friends of the first user and/or users tagged in the images).

In particular embodiments, the social-networking system 360 may present a “privacy wizard” (e.g., within a webpage, a module, one or more dialog boxes, or any other suitable interface) to the first user to assist the first user in specifying one or more privacy settings. The privacy wizard may display instructions, suitable privacy-related information, current privacy settings, one or more input fields for accepting one or more inputs from the first user specifying a change or confirmation of privacy settings, or any suitable combination thereof. In particular embodiments, the social-networking system 360 may offer a “dashboard” functionality to the first user that may display, to the first user, current privacy settings of the first user. The dashboard functionality may be displayed to the first user at any appropriate time (e.g., following an input from the first user summoning the dashboard functionality, following the occurrence of a particular event or trigger action). The dashboard functionality may allow the first user to modify one or more of the first user's current privacy settings at any time, in any suitable manner (e.g., redirecting the first user to the privacy wizard).

Privacy settings associated with an object may specify any suitable granularity of permitted access or denial of access. As an example and not by way of limitation, access or denial of access may be specified for particular users (e.g., only me, my roommates, my boss), users within a particular degree-of-separation (e.g., friends, friends-of-friends), user groups (e.g., the gaming club, my family), user networks (e.g., employees of particular employers, students or alumni of particular university), all users (“public”), no users (“private”), users of third-party systems 370, particular applications (e.g., third-party applications, external websites), other suitable entities, or any suitable combination thereof. Although this disclosure describes particular granularities of permitted access or denial of access, this disclosure contemplates any suitable granularities of permitted access or denial of access.

In particular embodiments, one or more servers of the social-networking system 360 may be authorization/privacy servers for enforcing privacy settings. In response to a request from a user (or other entity) for a particular object stored in a data store of the social-networking system 360, the social-networking system 360 may send a request to the data store for the object. The request may identify the user associated with the request and the object may be sent only to the user (or a client system 330 of the user) if the authorization server determines that the user is authorized to access the object based on the privacy settings associated with the object. If the requesting user is not authorized to access the object, the authorization server may prevent the requested object from being retrieved from the data store or may prevent the requested object from being sent to the user. In the search-query context, an object may be provided as a search result only if the querying user is authorized to access the object, e.g., if the privacy settings for the object allow it to be surfaced to, discovered by, or otherwise visible to the querying user. In particular embodiments, an object may represent content that is visible to a user through a newsfeed of the user. As an example and not by way of limitation, one or more objects may be visible to a user's “Trending” page. In particular embodiments, an object may correspond to a particular user. The object may be content associated with the particular user or may be the particular user's account or information stored on the social-networking system 360, or other computing system. As an example and not by way of limitation, a first user may view one or more second users of an online social network through a “People You May Know” function of the online social network, or by viewing a list of friends of the first user. As an example and not by way of limitation, a first user may specify that they do not wish to see objects associated with a particular second user in their newsfeed or friends list. If the privacy settings for the object do not allow it to be surfaced to, discovered by, or visible to the user, the object may be excluded from the search results. Although this disclosure describes enforcing privacy settings in a particular manner, this disclosure contemplates enforcing privacy settings in any suitable manner.

In particular embodiments, different objects of the same type associated with a user may have different privacy settings. Different types of objects associated with a user may have different types of privacy settings. As an example and not by way of limitation, a first user may specify that the first user's status updates are public, but any images shared by the first user are visible only to the first user's friends on the online social network. As another example and not by way of limitation, a user may specify different privacy settings for different types of entities, such as individual users, friends-of-friends, followers, user groups, or corporate entities. As another example and not by way of limitation, a first user may specify a group of users that may view videos posted by the first user, while keeping the videos from being visible to the first user's employer. In particular embodiments, different privacy settings may be provided for different user groups or user demographics. As an example and not by way of limitation, a first user may specify that other users who attend the same university as the first user may view the first user's pictures, but that other users who are family members of the first user may not view those same pictures.

In particular embodiments, the social-networking system 360 may provide one or more default privacy settings for each object of a particular object-type. A privacy setting for an object that is set to a default may be changed by a user associated with that object. As an example and not by way of limitation, all images posted by a first user may have a default privacy setting of being visible only to friends of the first user and, for a particular image, the first user may change the privacy setting for the image to be visible to friends and friends-of-friends.

In particular embodiments, privacy settings may allow a first user to specify (e.g., by opting out, by not opting in) whether the social-networking system 360 may receive, collect, log, or store particular objects or information associated with the user for any purpose. In particular embodiments, privacy settings may allow the first user to specify whether particular applications or processes may access, store, or use particular objects or information associated with the user. The privacy settings may allow the first user to opt in or opt out of having objects or information accessed, stored, or used by specific applications or processes. The social-networking system 360 may access such information in order to provide a particular function or service to the first user, without the social-networking system 360 having access to that information for any other purposes. Before accessing, storing, or using such objects or information, the social-networking system 360 may prompt the user to provide privacy settings specifying which applications or processes, if any, may access, store, or use the object or information prior to allowing any such action. As an example and not by way of limitation, a first user may transmit a message to a second user via an application related to the online social network (e.g., a messaging app), and may specify privacy settings that such messages should not be stored by the social-networking system 360.

In particular embodiments, a user may specify whether particular types of objects or information associated with the first user may be accessed, stored, or used by the social-networking system 360. As an example and not by way of limitation, the first user may specify that images sent by the first user through the social-networking system 360 may not be stored by the social-networking system 360. As another example and not by way of limitation, a first user may specify that messages sent from the first user to a particular second user may not be stored by the social-networking system 360. As yet another example and not by way of limitation, a first user may specify that all objects sent via a particular application may be saved by the social-networking system 360.

In particular embodiments, privacy settings may allow a first user to specify whether particular objects or information associated with the first user may be accessed from particular client systems 330 or third-party systems 370. The privacy settings may allow the first user to opt in or opt out of having objects or information accessed from a particular device (e.g., the phone book on a user's smart phone), from a particular application (e.g., a messaging app), or from a particular system (e.g., an email server). The social-networking system 360 may provide default privacy settings with respect to each device, system, or application, and/or the first user may be prompted to specify a particular privacy setting for each context. As an example and not by way of limitation, the first user may utilize a location-services feature of the social-networking system 360 to provide recommendations for restaurants or other places in proximity to the user. The first user's default privacy settings may specify that the social-networking system 360 may use location information provided from a client device 330 of the first user to provide the location-based services, but that the social-networking system 360 may not store the location information of the first user or provide it to any third-party system 370. The first user may then update the privacy settings to allow location information to be used by a third-party image-sharing application in order to geo-tag photos.

In particular embodiments, privacy settings may allow a user to specify one or more geographic locations from which objects can be accessed. Access or denial of access to the objects may depend on the geographic location of a user who is attempting to access the objects. As an example and not by way of limitation, a user may share an object and specify that only users in the same city may access or view the object. As another example and not by way of limitation, a first user may share an object and specify that the object is visible to second users only while the first user is in a particular location. If the first user leaves the particular location, the object may no longer be visible to the second users. As another example and not by way of limitation, a first user may specify that an object is visible only to second users within a threshold distance from the first user. If the first user subsequently changes location, the original second users with access to the object may lose access, while a new group of second users may gain access as they come within the threshold distance of the first user.

FIG. 5 illustrates an example computer system 500 in particular embodiments. In particular embodiments, one or more computer systems 500 perform one or more steps of one or more methods described or illustrated herein. In particular embodiments, one or more computer systems 500 provide functionality described or illustrated herein. In particular embodiments, software running on one or more computer systems 500 performs one or more steps of one or more methods described or illustrated herein or provides functionality described or illustrated herein. Particular embodiments include one or more portions of one or more computer systems 500. Herein, reference to a computer system may encompass a computing device, and vice versa, where appropriate. Moreover, reference to a computer system may encompass one or more computer systems, where appropriate.

This disclosure contemplates any suitable number of computer systems 500. This disclosure contemplates computer system 500 taking any suitable physical form. As example and not by way of limitation, computer system 500 may be an embedded computer system, a system-on-chip (SOC), a single-board computer system (SBC) (such as, for example, a computer-on-module (COM) or system-on-module (SOM)), a desktop computer system, a laptop or notebook computer system, an interactive kiosk, a mainframe, a mesh of computer systems, a mobile telephone, a personal digital assistant (PDA), a server, a tablet computer system, an augmented/virtual reality device, or a combination of two or more of these. Where appropriate, computer system 500 may include one or more computer systems 500; be unitary or distributed; span multiple locations; span multiple machines; span multiple data centers; or reside in a cloud, which may include one or more cloud components in one or more networks. Where appropriate, one or more computer systems 500 may perform without substantial spatial or temporal limitation one or more steps of one or more methods described or illustrated herein. As an example and not by way of limitation, one or more computer systems 500 may perform in real time or in batch mode one or more steps of one or more methods described or illustrated herein. One or more computer systems 500 may perform at different times or at different locations one or more steps of one or more methods described or illustrated herein, where appropriate.

In particular embodiments, computer system 500 includes a processor 502, memory 504, storage 506, an input/output (I/O) interface 508, a communication interface 510, and a bus 512. Although this disclosure describes and illustrates a particular computer system having a particular number of particular components in a particular arrangement, this disclosure contemplates any suitable computer system having any suitable number of any suitable components in any suitable arrangement.

In particular embodiments, processor 502 includes hardware for executing instructions, such as those making up a computer program. As an example and not by way of limitation, to execute instructions, processor 502 may retrieve (or fetch) the instructions from an internal register, an internal cache, memory 504, or storage 506; decode and execute them; and then write one or more results to an internal register, an internal cache, memory 504, or storage 506. In particular embodiments, processor 502 may include one or more internal caches for data, instructions, or addresses. This disclosure contemplates processor 502 including any suitable number of any suitable internal caches, where appropriate. As an example and not by way of limitation, processor 502 may include one or more instruction caches, one or more data caches, and one or more translation lookaside buffers (TLBs). Instructions in the instruction caches may be copies of instructions in memory 504 or storage 506, and the instruction caches may speed up retrieval of those instructions by processor 502. Data in the data caches may be copies of data in memory 504 or storage 506 for instructions executing at processor 502 to operate on; the results of previous instructions executed at processor 502 for access by subsequent instructions executing at processor 502 or for writing to memory 504 or storage 506; or other suitable data. The data caches may speed up read or write operations by processor 502. The TLBs may speed up virtual-address translation for processor 502. In particular embodiments, processor 502 may include one or more internal registers for data, instructions, or addresses. This disclosure contemplates processor 502 including any suitable number of any suitable internal registers, where appropriate. Where appropriate, processor 502 may include one or more arithmetic logic units (ALUs); be a multi-core processor; or include one or more processors 502. Although this disclosure describes and illustrates a particular processor, this disclosure contemplates any suitable processor.

In particular embodiments, memory 504 includes main memory for storing instructions for processor 502 to execute or data for processor 502 to operate on. As an example and not by way of limitation, computer system 500 may load instructions from storage 506 or another source (such as, for example, another computer system 500) to memory 504. Processor 502 may then load the instructions from memory 504 to an internal register or internal cache. To execute the instructions, processor 502 may retrieve the instructions from the internal register or internal cache and decode them. During or after execution of the instructions, processor 502 may write one or more results (which may be intermediate or final results) to the internal register or internal cache. Processor 502 may then write one or more of those results to memory 504. In particular embodiments, processor 502 executes only instructions in one or more internal registers or internal caches or in memory 504 (as opposed to storage 506 or elsewhere) and operates only on data in one or more internal registers or internal caches or in memory 504 (as opposed to storage 506 or elsewhere). One or more memory buses (which may each include an address bus and a data bus) may couple processor 502 to memory 504. Bus 512 may include one or more memory buses, as described below. In particular embodiments, one or more memory management units (MMUs) reside between processor 502 and memory 504 and facilitate accesses to memory 504 requested by processor 502. In particular embodiments, memory 504 includes random access memory (RAM). This RAM may be volatile memory, where appropriate. Where appropriate, this RAM may be dynamic RAM (DRAM) or static RAM (SRAM). Moreover, where appropriate, this RAM may be single-ported or multi-ported RAM. This disclosure contemplates any suitable RAM. Memory 504 may include one or more memories 504, where appropriate. Although this disclosure describes and illustrates particular memory, this disclosure contemplates any suitable memory.

In particular embodiments, storage 506 includes mass storage for data or instructions. As an example and not by way of limitation, storage 506 may include a hard disk drive (HDD), a floppy disk drive, flash memory, an optical disc, a magneto-optical disc, magnetic tape, or a Universal Serial Bus (USB) drive or a combination of two or more of these. Storage 506 may include removable or non-removable (or fixed) media, where appropriate. Storage 506 may be internal or external to computer system 500, where appropriate. In particular embodiments, storage 506 is non-volatile, solid-state memory. In particular embodiments, storage 506 includes read-only memory (ROM). Where appropriate, this ROM may be mask-programmed ROM, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), electrically alterable ROM (EAROM), or flash memory or a combination of two or more of these. This disclosure contemplates mass storage 506 taking any suitable physical form. Storage 506 may include one or more storage control units facilitating communication between processor 502 and storage 506, where appropriate. Where appropriate, storage 506 may include one or more storages 506. Although this disclosure describes and illustrates particular storage, this disclosure contemplates any suitable storage.

In particular embodiments, I/O interface 508 includes hardware, software, or both, providing one or more interfaces for communication between computer system 500 and one or more I/O devices. Computer system 500 may include one or more of these I/O devices, where appropriate. One or more of these I/O devices may enable communication between a person and computer system 500. As an example and not by way of limitation, an I/O device may include a keyboard, keypad, microphone, monitor, mouse, printer, scanner, speaker, still camera, stylus, tablet, touch screen, trackball, video camera, another suitable I/O device or a combination of two or more of these. An I/O device may include one or more sensors. This disclosure contemplates any suitable I/O devices and any suitable I/O interfaces 508 for them. Where appropriate, I/O interface 508 may include one or more device or software drivers enabling processor 502 to drive one or more of these I/O devices. I/O interface 508 may include one or more I/O interfaces 508, where appropriate. Although this disclosure describes and illustrates a particular I/O interface, this disclosure contemplates any suitable I/O interface.

In particular embodiments, communication interface 510 includes hardware, software, or both providing one or more interfaces for communication (such as, for example, packet-based communication) between computer system 500 and one or more other computer systems 500 or one or more networks. As an example and not by way of limitation, communication interface 510 may include a network interface controller (NIC) or network adapter for communicating with an Ethernet or other wire-based network or a wireless NIC (WNIC) or wireless adapter for communicating with a wireless network, such as a WI-FI network. This disclosure contemplates any suitable network and any suitable communication interface 510 for it. As an example and not by way of limitation, computer system 500 may communicate with an ad hoc network, a personal area network (PAN), a local area network (LAN), a wide area network (WAN), a metropolitan area network (MAN), or one or more portions of the Internet or a combination of two or more of these. One or more portions of one or more of these networks may be wired or wireless. As an example, computer system 500 may communicate with a wireless PAN (WPAN) (such as, for example, a BLUETOOTH WPAN), a WI-FI network, a WI-MAX network, a cellular telephone network (such as, for example, a Global System for Mobile Communications (GSM) network), or other suitable wireless network or a combination of two or more of these. Computer system 500 may include any suitable communication interface 510 for any of these networks, where appropriate. Communication interface 510 may include one or more communication interfaces 510, where appropriate. Although this disclosure describes and illustrates a particular communication interface, this disclosure contemplates any suitable communication interface.

In particular embodiments, bus 512 includes hardware, software, or both coupling components of computer system 500 to each other. As an example and not by way of limitation, bus 512 may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a front-side bus (FSB), a HYPERTRANSPORT (HT) interconnect, an Industry Standard Architecture (ISA) bus, an INFINIBAND interconnect, a low-pin-count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCIe) bus, a serial advanced technology attachment (SATA) bus, a Video Electronics Standards Association local (VLB) bus, or another suitable bus or a combination of two or more of these. Bus 512 may include one or more buses 512, where appropriate. Although this disclosure describes and illustrates a particular bus, this disclosure contemplates any suitable bus or interconnect.

Herein, a computer-readable non-transitory storage medium or media may include one or more semiconductor-based or other integrated circuits (ICs) (such, as for example, field-programmable gate arrays (FPGAs) or application-specific ICs (ASICs)), hard disk drives (HDDs), hybrid hard drives (HHDs), optical discs, optical disc drives (ODDs), magneto-optical discs, magneto-optical drives, floppy diskettes, floppy disk drives (FDDs), magnetic tapes, solid-state drives (SSDs), RAM-drives, SECURE DIGITAL cards or drives, any other suitable computer-readable non-transitory storage media, or any suitable combination of two or more of these, where appropriate. A computer-readable non-transitory storage medium may be volatile, non-volatile, or a combination of volatile and non-volatile, where appropriate.

Herein, “or” is inclusive and not exclusive, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A or B” means “A, B, or both,” unless expressly indicated otherwise or indicated otherwise by context. Moreover, “and” is both joint and several, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A and B” means “A and B, jointly or severally,” unless expressly indicated otherwise or indicated otherwise by context.

The scope of this disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments described or illustrated herein that a person having ordinary skill in the art would comprehend. The scope of this disclosure is not limited to the example embodiments described or illustrated herein. Moreover, although this disclosure describes and illustrates respective embodiments herein as including particular components, elements, feature, functions, operations, or steps, any of these embodiments may include any combination or permutation of any of the components, elements, features, functions, operations, or steps described or illustrated anywhere herein that a person having ordinary skill in the art would comprehend. Furthermore, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative. Additionally, although this disclosure describes or illustrates particular embodiments as providing particular advantages, particular embodiments may provide none, some, or all of these advantages. 

What is claimed is:
 1. A method comprising: by a computing system, receiving signals periodically detected by a mobile computing device, wherein the detected signals are transmitted from a plurality of signal sources within an environment; by the computing system, determining a spatial distribution of signal strengths with respect to the detected signals; by the computing system, identifying a plurality of relative positions based on at least the spatial distribution of signal strengths, wherein the plurality of relative positions are the mobile computing device's relative locations with respect to the environment; by the computing system, receiving a plurality of images of the environment captured by a camera of the mobile computing device; by the computing system, creating image analysis results by analyzing the plurality of images, wherein analyzing the plurality of images comprises identifying an entrance or exit of a place of interest by analyzing movements of one or more persons captured in the plurality of images; by the computing system, calibrating the plurality of relative positions based on the image analysis results, wherein at least one of the relative positions is calibrated based on the identified entrance or exit of the place of interest; and by the computer system, creating a map of spatial distribution of signal strengths by correlating the spatial distribution of signal strengths with the plurality of relative positions that have been calibrated based on the image analysis results.
 2. The method of claim 1, further comprising, by the computing system: receiving motion data of the mobile computing device, wherein the motion data is detected by various motion sensors including one or more of a compass, an accelerometer, an altimeter, a camera sensor, or a gyroscope; and calibrating the plurality of relative positions using with the motion data.
 3. The method of claim 2, further comprising, by the computing system, generating a 3-dimension (3D) map of the environment by analyzing the plurality of images or the motion data using an augmented reality (AR) technique.
 4. The method of claim 3, wherein the environment comprises a plurality of floors, and wherein the 3D map is generated to display the plurality of floors within the environment.
 5. The method of claim 1, further comprising, by the computing system: receiving signals detected by a second mobile computing device, wherein the second mobile computing device periodically detects signals transmitted from the plurality of signal sources within the environment; determining a second spatial distribution of signal strengths with respect to the signals detected by the second mobile computing device; identifying a relative position with respect to the environment of the second mobile computing device on the map of spatial distribution of signal strengths in accordance with the determined second spatial distribution of signal strengths; and providing an AR content item for display to the second mobile computing device, wherein the AR content item is determined based on at least the identified relative position with respect to the environment of the second mobile computing device.
 6. The method of claim 1, further comprising, by the computing system: determining a starting point of the mobile computing device within the environment, wherein identifying the plurality of relative positions is further based on the starting point of the mobile computing device.
 7. The method of claim 1, further comprising, by the computing system: normalizing a list of scatter points to a grid, wherein each scattered point of the grid associates with a set of signals detected from respective signal sources at a sampling location; and forming the spatial distribution of signal strengths indicated by the set of signals by interpolating distribution of signal strengths at each scattered point of the grid.
 8. The method of claim 1, further comprising, by the computing system: storing the map of spatial distribution of signal strengths in a storage component of the computing system; and updating the map of spatial distribution of signal strengths by crowdsourcing signal strengths collected from multiple devices within the environment over a predetermined period of time.
 9. The method of claim 1, wherein the map of spatial distribution of signal strengths includes the spatial distribution of signal strengths on each of a plurality of floors within the environment.
 10. The method of claim 1, wherein the spatial distribution of signal strengths is weighted in accordance with the mobile computing device.
 11. The method of claim 1, further comprising, by the computing system, providing information configured to display a virtual path on the second mobile computing device, wherein the virtual path is created based on the map of spatial distribution of signal strengths.
 12. The method of claim 1, further comprising, by the computing system, obtaining space information of the environment by analyzing the plurality of images or the motion data detected by motion sensors.
 13. The method of claim 1, further comprising, by the computing system, updating location information of the signal sources when the signal sources are relocated.
 14. The method of claim 1, further comprising, by the computing system: expiring a signal source from the map of spatial distribution of signal strengths when the said signal source is not encountered by a mobile computing device for a predetermined amount of time; and restoring the said signal source on the map of spatial distribution of signal strengths when the signal source is re-encountered by a mobile computing device.
 15. The method of claim 1, further comprising, by the computing system, determining orientation of the mobile computing device based on information from a gyroscope.
 16. The method of claim 1, further comprising, by the computing system, determining acceleration of the mobile computing device based on information from an accelerometer.
 17. The method of claim 1, further comprising, by the computing system: selecting an AR algorithm from a plurality of AR algorithms with respect to at least characteristics of the plurality of images or the environment; and processing the plurality of images using the selected AR algorithm.
 18. The method of claim 1, further comprising, by the computing system, identifying an absolute location of the mobile computing device based on location signals from a global positioning satellite (GPS).
 19. A system comprising: one or more processors; and a memory coupled to the processors comprising instructions executable by the processors, the processors executing the instructions to: receive signals detected by a mobile computing device, wherein the mobile computing device periodically detects signals transmitted from a plurality of signal sources within an environment; determine a spatial distribution of signal strengths with respect to the detected signals; identify a plurality of relative positions based on at least the spatial distribution of signal strengths, wherein the plurality of relative positions are the mobile computing device's relative locations with respect to the environment; receive a plurality of images of the environment captured by a camera of the mobile computing device; create image analysis results by analyzing the plurality of images, wherein analyzing the plurality of images comprises identifying an entrance or exit of a place of interest by analyzing movements of one or more persons captured in the plurality of images; calibrate the plurality of relative positions based on the image analysis results, wherein at least one of the relative positions is calibrated based on the identified entrance or exit of the place of interest; and create a map of spatial distribution of signal strengths by correlating the spatial distribution of signal strengths with the plurality of relative positions that have been calibrated based on the image analysis results.
 20. One or more computer-readable non-transitory storage media embodying software that is executed to: receive signals detected by a mobile computing device, wherein the mobile computing device periodically detects signals transmitted from a plurality of signal sources within an environment; determine a spatial distribution of signal strengths with respect to the detected signals; identify a plurality of relative positions based on at least the spatial distribution of signal strengths, wherein the plurality of relative positions are the mobile computing device's relative locations with respect to the environment; receive a plurality of images of the environment captured by a camera of the mobile computing device; create image analysis results by analyzing the plurality of images, wherein analyzing the plurality of images comprises identifying an entrance or exit of a place of interest by analyzing movements of one or more persons captured in the plurality of images; calibrate the plurality of relative positions based on the image analysis results, wherein at least one of the relative positions is calibrated based on the identified entrance or exit of the place of interest; and create a map of spatial distribution of signal strengths by correlating the spatial distribution of signal strengths with the plurality of relative positions that have been calibrated based on the image analysis results. 